nsfs: generalize ns_get_path() for path resolution with a task

ns_get_path() takes struct task_struct and proc_ns_ops as its parameters. For path resolution directly from a namespace, e.g. based on a networking device's net name space, we need more flexibility. Add a ns_get_path_cb() helper which will allow callers to use any method of obtaining the name space reference. Convert ns_get_path() to use ns_get_path_cb(). Following patches will bring a networking user.

Jakub Kicinski committed 8 years ago

Commit cdab6ba1 parent ad8ad792 files · +29 −3Browse files

Unified · Split

2 files

fs/nsfs.c +26 −3
include/linux/proc_ns.h +3 −0

fs/nsfs.c+26−3

@@ -103,14 +103,14 @@ slow: · 102 unmodified lines
103	103	goto got_it;
104	104	}
105	105
106		−void ns_get_path(struct path path, struct task_struct *task,
107		− const struct proc_ns_operations *ns_ops)
	106	+void ns_get_path_cb(struct path path, ns_get_path_helper_t *ns_get_cb,
	107	+ void *private_data)
108	108	{
109	109	struct ns_common *ns;
110	110	void *ret;
111	111
112	112	again:
113		− ns = ns_ops->get(task);
	113	+ ns = ns_get_cb(private_data);
114	114	if (!ns)
115	115	return ERR_PTR(-ENOENT);
116	116
@@ -120,6 +120,29 @@ again: · 3 unmodified lines
120	120	return ret;
121	121	}
122	122
	123	+struct ns_get_path_task_args {
	124	+ const struct proc_ns_operations *ns_ops;
	125	+ struct task_struct *task;
	126	+};
	127	+
	128	+static struct ns_common ns_get_path_task(void private_data)
	129	+{
	130	+ struct ns_get_path_task_args *args = private_data;
	131	+
	132	+ return args->ns_ops->get(args->task);
	133	+}
	134	+
	135	+void ns_get_path(struct path path, struct task_struct *task,
	136	+ const struct proc_ns_operations *ns_ops)
	137	+{
	138	+ struct ns_get_path_task_args args = {
	139	+ .ns_ops = ns_ops,
	140	+ .task = task,
	141	+ };
	142	+
	143	+ return ns_get_path_cb(path, ns_get_path_task, &args);
	144	+}
	145	+
123	146	int open_related_ns(struct ns_common *ns,
124	147	struct ns_common (get_ns)(struct ns_common *ns))
125	148	{

include/linux/proc_ns.h+3−0

@@ -78,6 +78,9 @@ extern struct file *proc_ns_fget(int fd); · 77 unmodified lines
78	78	#define get_proc_ns(inode) ((struct ns_common *)(inode)->i_private)
79	79	extern void ns_get_path(struct path path, struct task_struct *task,
80	80	const struct proc_ns_operations *ns_ops);
	81	+typedef struct ns_common ns_get_path_helper_t(void );
	82	+extern void ns_get_path_cb(struct path path, ns_get_path_helper_t ns_get_cb,
	83	+ void *private_data);
81	84
82	85	extern int ns_get_name(char buf, size_t size, struct task_struct task,
83	86	const struct proc_ns_operations *ns_ops);